Process for the cracking of oils



Patented Mar. 9,1943 1 raocass roa run onAcNG or orLs Alfred Claude Jessup, Clamart, France, assignor to @harlcs Wei at t i- London, England 2 laims.

one would obtain if one used separately each of the two catalysts in question. Without in any way limiting myself to the following assumption it seems probable that the atoms forming the catalyst produce a coupling effect and thus introduce a new factor and increasethe activation of the reaction.

In particular I have found that in this way i one can obtain a remarkable desulfurisation of the products treated, approximately 70% of the sulfur contained in the raw oil being converted intonon volatile metallic sulfides. I have further found that, either as a result of this 'desulfurisation or as a result of the direct nature of their activity, the atoms forming the catalyst have the effect of enabling the cracking to take place at a comparatively low temperature, and in particular ameliorate the results obtained in the liquid phase.

The present invention consequently consists in carrying out the operation of cracking in the presence of a mixture of more than one metallic catalyst. In the preferred manner of putting my invention into execution I employ as catalysts iron and copper in a suitably finely divided state. It is not necessary however for both metals to be in the finely divided state: thus I have obtained excellent results using finely divided iron in an apparatus made of copper.

It is advantageous to carry out the reaction in the presence of hydrogen which can be added at the commencement: but this addition of hydrogen is by no means indispensable. The presence of hydrogen tends to diminish firstly the quantity of coke formed and secondly the formation of unsaturated .products resulting from the liberation of hydrogen at the cost of the liquid products obtained as the result of cracking. An initial pressure of 10 to 20 atmospheres of hydrogen has given good results.

It is obvious that the effect of the addition of hydrogen is not to produce a true hydrogenation inasmuch as the metals employed are not hydrogenation catalysts. The above result is due rather to a displacement of the equilibrium between the saturated and unsaturated products of the cracking owing to the addition of one of the substances which take part in the equilibrium in question, in other words hydrogen.

By way of an example which is by no means limitative, one may proceed as follows in carrying out my invention. A mixture of gas oil and tar in the proportion of 180 parts of gas oil to 120 parts of tar, containing 2.3% of sulfur, is treated in acopper apparatus in the presence of freshly reduced iron. The operation is carried through at 380 C., in the presence of hydrogen under a pressure of 10 atmospheres, the heating being maintained for a considerable period of time, say for example for longer than 10 hours. One subsequently finds a considerable increase in volatile products of low boiling point together with the formation of iron sulfide and a concomitant decrease in the sulfur content of the volatile products.

I claim:

1. A process of cracking an oil material which comprises subjecting such oil material to the action of hydrogen gas introduced as such, under a pressure of several atmospheres, while in the presence of freshly reduced iron while, in a copper apparatus, at a temperature of about 380 C., until the sulfur content of the oil is substantially lowered, and until a substantial amount of low boiling hydrocarbons have been produced. v

2. A process of cracking an oil material which comprises subjecting such oil material to the actionof molecular hydrogen introduced as such, under a pressure of about 10 to about '20 atmospheres, while in the presence of freshly reduced 'iron while in a copper apparatus, at a temperature of about 380 C., until the sulfur content of the oil is substantially lowered, and until a substantial amount of low boiling hydrocarbons have been produced, the said iron being present in the reaction materials throughout the entire process.

ALFRED CLAUDE JESSU' 

